gfs2: Convert gfs2_internal_read to folios

Change gfs2_internal_read() to use folios.  Convert sizes to size_t.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/aops.c

@@ -477,31 +477,29 @@ static int gfs2_read_folio(struct file *file, struct folio *folio)
  *
  */
 
-int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
-                       unsigned size)
+ssize_t gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
+			   size_t size)
 {
 	struct address_space *mapping = ip->i_inode.i_mapping;
 	unsigned long index = *pos >> PAGE_SHIFT;
-	unsigned offset = *pos & (PAGE_SIZE - 1);
-	unsigned copied = 0;
-	unsigned amt;
-	struct page *page;
+	size_t copied = 0;
 
 	do {
-		page = read_cache_page(mapping, index, gfs2_read_folio, NULL);
-		if (IS_ERR(page)) {
-			if (PTR_ERR(page) == -EINTR)
+		size_t offset, chunk;
+		struct folio *folio;
+
+		folio = read_cache_folio(mapping, index, gfs2_read_folio, NULL);
+		if (IS_ERR(folio)) {
+			if (PTR_ERR(folio) == -EINTR)
 				continue;
-			return PTR_ERR(page);
+			return PTR_ERR(folio);
 		}
-		amt = size - copied;
-		if (offset + size > PAGE_SIZE)
-			amt = PAGE_SIZE - offset;
-		memcpy_from_page(buf + copied, page, offset, amt);
-		put_page(page);
-		copied += amt;
-		index++;
-		offset = 0;
+		offset = *pos + copied - folio_pos(folio);
+		chunk = min(size - copied, folio_size(folio) - offset);
+		memcpy_from_folio(buf + copied, folio, offset, chunk);
+		index = folio_next_index(folio);
+		folio_put(folio);
+		copied += chunk;
 	} while(copied < size);
 	(*pos) += size;
 	return size;

fs/gfs2/inode.h

@@ -13,8 +13,8 @@
 #include "util.h"
 
 bool gfs2_release_folio(struct folio *folio, gfp_t gfp_mask);
-extern int gfs2_internal_read(struct gfs2_inode *ip,
-			      char *buf, loff_t *pos, unsigned size);
+extern ssize_t gfs2_internal_read(struct gfs2_inode *ip,
+				  char *buf, loff_t *pos, size_t size);
 extern void gfs2_set_aops(struct inode *inode);
 
 static inline int gfs2_is_stuffed(const struct gfs2_inode *ip)